Production method for water jacket spacer

ABSTRACT

A method for producing a water jacket spacer includes using an injection mold that forms a molding space, the molding space producing an integrally molded product that includes at least a first water jacket spacer, a second water jacket spacer, and a bridge, the first water jacket spacer and the second water jacket spacer being provided so that the inner sides thereof are situated opposite to each other, and the bridge linking the inner side or the end of the first water jacket spacer, and the inner side or the end of the second water jacket spacer. The method for producing a water jacket spacer can produce a water jacket spacer having a shape that corresponds to half or part of half of the groove-like coolant passage along the circumferential direction by means of injection molding while preventing the occurrence of an adhesion-to-slide phenomenon when the mold is opened.

TECHNICAL FIELD

The present invention relates to a method for producing a water jacketspacer that is disposed in a groove-like coolant passage formed in acylinder block provided to an internal combustion engine.

BACKGROUND ART

An internal combustion engine is designed so that fuel explodes withinthe cylinder bore when the piston is positioned at top dead center, andthe piston is moved downward due to the explosion. Therefore, the upperpart of the cylinder bore wall increases in temperature as compared withthe lower part of the cylinder bore wall. Accordingly, a difference inthe amount of thermal deformation occurs between the upper part and thelower part of the cylinder bore wall (i.e., the upper part of thecylinder bore wall expands to a large extent as compared with the lowerpart of the cylinder bore wall).

As a result, the frictional resistance of the piston against thecylinder bore wall increases, and the fuel consumption increases.Therefore, a reduction in difference in the amount of thermaldeformation between the upper part and the lower part of the cylinderbore wall has been desired.

FIG. 1 illustrates an example of a cylinder block. The cylinder blockincludes a plurality of cylinder bores that are formed in series, and agroove-like coolant passage is formed to completely surround eachcylinder bore.

Attempts have been made to control the cooling efficiency in the upperpart and the lower part of the cylinder bore wall due to the coolant bydisposing a water jacket spacer in a groove-like coolant passage toadjust the flow of the coolant in the groove-like coolant passage sothat the cylinder bore wall has a uniform temperature. For example,Patent Literature 1 discloses an internal combustion engine heatingmedium passage partition member that is disposed in a groove-likeheating medium passage formed in a cylinder block of an internalcombustion engine to divide the groove-like heating medium passage intoa plurality of passages, the heating medium passage partition memberincluding a passage division member that is formed at a height above thebottom of the groove-like heating medium passage, and serves as a wallthat divides the groove-like heating medium passage into a bore-sidepassage and a non-bore-side passage, and a flexible lip member that isformed from the passage division member in the opening direction of thegroove-like heating medium passage, the edge area of the flexible lipmember being formed of a flexible material to extend beyond the innersurface of one of the groove-like heating medium passages, and coming incontact with the inner surface at a middle position of the groove-likeheating medium passage in the depth direction due to the flexurerestoring force after insertion into the groove-like heating mediumpassage to separate the bore-side passage and the non-bore-side passage.

CITATION LIST Patent Literature

-   Patent Literature 1: JP-A-2008-31939 (claims)

SUMMARY OF INVENTION Technical Problem

A known water jacket spacer that is disposed in the groove-like coolantpassage provided to the cylinder block has a shape that surrounds theentirety of the cylinder bores. For example, a water jacket spacer 40illustrated in FIG. 28 has a shape that surrounds the entirety of thecylinder bores (i.e., a tubular water jacket spacer that is constrictedat three positions that correspond to an area between the cylinderbores) is disposed in the groove-like coolant passage provided to thecylinder block illustrated in FIG. 1. The water jacket spacer disclosedin Patent Literature 1 has a shape that surrounds the entirety of thecylinder bores.

Such a water jacket spacer is produced by subjecting a synthetic resinto an injection molding process.

Since the water jacket spacer that has a shape that surrounds theentirety of the cylinder bores extends through the entirety of thegroove-like coolant passage provided to the cylinder block along thecircumferential direction, it is difficult to selectively andsignificantly change the flow rate of the coolant using such a waterjacket spacer with respect to part of the groove-like coolant passagealong the circumferential direction.

In order to selectively (partially) control the flow rate of the coolantthat flows through the groove-like coolant passage, it is necessary toprovide a water jacket spacer that has a shape that corresponds to partof the groove-like coolant passage along the circumferential direction.For example, it is necessary to use a water jacket spacer 1 a or 1 billustrated in FIG. 2. The water jacket spacer 1 a has a shape thatcorresponds to half of the groove-like coolant passage provided to thecylinder block (see FIG. 1) along the circumferential direction, and thewater jacket spacer 1 b has a shape that corresponds to part (twointermediate bores) of half of the groove-like coolant passage providedto the cylinder block (see FIG. 1) along the circumferential direction.

Such a water jacket spacer is also produced by means of an injectionmolding process. The injection molding process that is used to producesuch a water jacket spacer utilizes an injection mold 41 illustrated inFIGS. 29 and 30 that forms a molding space 42 that produces a moldedproduct in which the inner sides of two water jacket spacers aresituated opposite to each other, from the viewpoint of productionefficiency. Note that the molded product obtained by the injectionmolding process includes a main body, a spool that serves as a moltenresin passage that extends from a nozzle of an injection molding machineto a runner, a runner that serves as an intermediate molten resinpassage that extends from the spool to a gate, and a gate that serves asan inlet through which a molten resin flows from the runner into themolding space (main body molding space).

The injection molding process that is used to produce a molded productin which the inner sides of two water jacket spacers are situatedopposite to each other, may utilize an injection mold that includes astationary mold, a movable mold that moves in the upward-downwarddirection with respect to the water jacket spacer, and a slide mold thatmoves in a direction at an angle of ±15° or less with respect to adirection that is perpendicular to the direction in which the cylinderbores are arranged, and is perpendicular to the moving direction of themovable mold, and forms a molding space that produces a molded productin which the inner sides of two water jacket spacers are situatedopposite to each other, when clamped, clamp the injection mold, inject asynthetic resin in a molten state, cool/solidify the synthetic resinwhile keeping pressure, open the injection mold, and remove the moldedproduct from the movable mold, for example.

When such an injection molding process is used, since the main body ofthe molded product adheres to the injection mold before the injectionmold is opened, the main body is pulled by the slide mold when the slidemold moves in a direction at an angle of ±15° or less with respect to adirection that is perpendicular to a direction in which the cylinderbores are arranged, and is perpendicular to the moving direction of themovable mold, so as to move away from the main body. Since the ends ofthe two water jacket spacers that are designed to be disposed in half orpart of half of the groove-like coolant passage are not liked to eachother, an adhesion-to-slide phenomenon in which the main body adheres toand is pulled by the slide mold occurs when the injection mold isopened.

The above injection molding process is normally computer-controlled sothat the clamping step, the injection step, the solidification step, themold-opening step, and the ejection step are automatically performed,and the mold-opening step is programmed so that the molded product thatadheres to the movable mold is removed. Therefore, it is impossible toimplement normal operation if an adhesion-to-slide phenomenon hasoccurred.

An object of the invention is to provide a method for producing a waterjacket spacer that can produce a water jacket spacer having a shape thatcorresponds to part of the groove-like coolant passage in thecircumferential direction by means of injection molding while preventingthe occurrence of an adhesion-to-slide phenomenon when the mold isopened.

Solution to Problem

According to one aspect of the invention, the above technical problem issolved by the following method for producing a water jacket spacer.

(1) A method for producing a water jacket spacer including subjecting asynthetic resin to an injection molding process to produce a waterjacket spacer, the water jacket spacer being disposed in the entirety orpart of a groove-like coolant passage along a circumferential direction,the groove-like coolant passage being provided to a cylinder block of aninternal combustion engine that has cylinder bores,

the injection molding process including a clamping step that clamps aninjection mold, an injection step that injects the synthetic resin in amolten state, a solidification step that cools and solidifies thesynthetic resin while keeping pressure, a mold-opening step that opensthe injection mold, and an ejection step that ejects an integrallymolded product from the injection mold,

the injection mold including a stationary mold, a movable mold thatmoves in an upward-downward direction with respect to the water jacketspacer, and at least one slide mold (1) that moves in a direction at anangle of ±15° or less with respect to a direction that is perpendicularto a direction in which the cylinder bores are arranged, and isperpendicular to a moving direction of the movable mold, and forming amolding space when clamped by the clamping step, the molding spaceproducing the integrally molded product that includes at least a firstwater jacket spacer, a second water jacket spacer, and a bridge, thefirst water jacket spacer and the second water jacket spacer beingprovided so that the inner sides thereof are situated opposite to eachother, and the bridge linking the inner side or the end of the firstwater jacket spacer, and the inner side or the end of the second waterjacket spacer, and

the mold-opening step moving the movable mold in the upward-downwarddirection with respect to the water jacket spacer, and moving the slidemold (1) in a direction at an angle of ±15° or less with respect to thedirection that is perpendicular to the direction in which the cylinderbores are arranged, and is perpendicular to the moving direction of themovable mold, to open the injection mold.

(2) The method for producing a water jacket spacer according to (1),wherein the bridge includes an inter-bore bridge that links an innerside of an inter-bore part of the first water jacket spacer, and aninner side of an inter-bore part of the second water jacket spacer, andan end bridge that links the end of the first water jacket spacer andthe end of the second water jacket spacer.(3) The method for producing a water jacket spacer according to (2),wherein the integrally molded product further includes an inter-bridgebridge that links a center area of the inter-bore bridge and a centerarea of the end bridge that is situated adjacent to the inter-borebridge, or links center areas of the inter-bore bridges that aresituated adjacent to each other.

Advantageous Effects of Invention

One aspect of the invention thus provides a method for producing a waterjacket spacer that can produce a water jacket spacer having a shape thatcorresponds to part of the groove-like coolant passage in thecircumferential direction by means of injection molding while preventingthe occurrence of an adhesion-to-slide phenomenon when the mold isopened.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic plan view illustrating an example of a cylinderblock in which a water jacket spacer is disposed.

FIG. 2 is a schematic perspective view illustrating an example of awater jacket spacer that is produced using a method for producing awater jacket spacer according to one embodiment of the invention.

FIG. 3 is a schematic end view illustrating an injection molding processthat is implemented by a method for producing a water jacket spaceraccording to one embodiment of the invention.

FIG. 4 is a schematic end view illustrating an injection molding processthat is implemented by a method for producing a water jacket spaceraccording to one embodiment of the invention.

FIG. 5 is a schematic end view illustrating an injection molding processthat is implemented by a method for producing a water jacket spaceraccording to one embodiment of the invention.

FIG. 6 is a schematic end view illustrating an injection molding processthat is implemented by a method for producing a water jacket spaceraccording to one embodiment of the invention.

FIG. 7 is a schematic end view illustrating an injection molding processthat is implemented by a method for producing a water jacket spaceraccording to one embodiment of the invention.

FIG. 8 is a schematic end view illustrating an injection molding processthat is implemented by a method for producing a water jacket spaceraccording to one embodiment of the invention.

FIG. 9 is a schematic perspective view illustrating an example of anintegrally molded product that is produced using a method for producinga water jacket spacer according to one embodiment of the invention.

FIG. 10 is a schematic end view illustrating an injection moldingprocess that is implemented by a method for producing a water jacketspacer according to one embodiment of the invention.

FIG. 11 is a schematic end view illustrating an injection moldingprocess that is implemented by a method for producing a water jacketspacer according to one embodiment of the invention.

FIG. 12 is a schematic end view illustrating an injection moldingprocess that is implemented by a method for producing a water jacketspacer according to one embodiment of the invention.

FIG. 13 is a schematic end view illustrating an injection moldingprocess that is implemented by a method for producing a water jacketspacer according to one embodiment of the invention.

FIG. 14 is a schematic end view illustrating an injection moldingprocess that is implemented by a method for producing a water jacketspacer according to one embodiment of the invention.

FIG. 15 is a schematic end view illustrating an injection moldingprocess that is implemented by a method for producing a water jacketspacer according to one embodiment of the invention.

FIG. 16 is a schematic end view illustrating an injection moldingprocess that is implemented by a method for producing a water jacketspacer according to one embodiment of the invention.

FIG. 17 is a schematic end view illustrating an injection moldingprocess that is implemented by a method for producing a water jacketspacer according to one embodiment of the invention.

FIG. 18 is a schematic end view illustrating an injection moldingprocess that is implemented by a method for producing a water jacketspacer according to one embodiment of the invention.

FIG. 19 is a schematic end view illustrating an injection moldingprocess that is implemented by a method for producing a water jacketspacer according to one embodiment of the invention.

FIG. 20 is a schematic end view illustrating an injection moldingprocess that is implemented by a method for producing a water jacketspacer according to one embodiment of the invention.

FIG. 21 is a schematic plan view illustrating an example of anintegrally molded product.

FIG. 22 is a schematic perspective view illustrating an example of anintegrally molded product.

FIG. 23 is a schematic plan view illustrating an example of anintegrally molded product.

FIG. 24 is a schematic plan view illustrating an example of anintegrally molded product.

FIG. 25 is a schematic plan view illustrating an example of a bridge.

FIG. 26 is a schematic plan view illustrating an example of anintegrally molded product.

FIG. 27 is a schematic plan view illustrating an example of anintegrally molded product.

FIG. 28 is a schematic perspective view illustrating a known waterjacket spacer.

FIG. 29 is a perspective view illustrating a virtual mold.

FIG. 30 is a plan view illustrating the virtual mold illustrated in FIG.29.

DESCRIPTION OF EMBODIMENTS

A method for producing a water jacket spacer according to one embodimentof the invention is described below with reference to FIGS. 1 to 9. FIG.1 is a schematic plan view illustrating an example of a cylinder blockin which a water jacket spacer that is produced using the method forproducing a water jacket spacer according to one embodiment of theinvention, is disposed. FIG. 2 is a schematic perspective viewillustrating an example of a water jacket spacer that is produced usingthe method for producing a water jacket spacer according to oneembodiment of the invention. FIGS. 3 to 8 are schematic end viewsillustrating an example of an injection molding process that isimplemented by the method for producing a water jacket spacer accordingto one embodiment of the invention. FIG. 9 is a schematic viewillustrating an example of an integrally molded product that is producedusing the method for producing a water jacket spacer according to oneembodiment of the invention, wherein (A) is a perspective view, and (B)is a top view.

The water jacket spacer 1 a illustrated in FIG. 2 is produced using themethod for producing a water jacket spacer according to one embodimentof the invention, and is disposed in a cylinder block 11 illustrated inFIG. 1. The water jacket spacer 1 a is disposed in the open-deckcylinder block 11 provided to an internal combustion engine that ismounted on a vehicle (see FIG. 1). The cylinder block 11 includes bores12 and a groove-like coolant passage 14, a piston moving upward anddownward in each bore 12, and a coolant flowing through the groove-likecoolant passage 14. The boundary between the bores 12 and thegroove-like coolant passage 14 is defined by a cylinder bore wall 13.The cylinder block 11 also includes a coolant inlet 15 for supplying thecoolant to the groove-like coolant passage 11, and a coolant outlet 16for discharging the coolant from the groove-like coolant passage 11.

The cylinder block 11 includes two or more bores 12 that are formed(arranged) in series. Specifically, the bores 12 include end bores 12 a1 and 12 a 2 that are formed to be adjacent to one bore, andintermediate bores 12 b 1 and 12 b 2 that are formed between two bores.Note that only the end bores are provided when the number of boresformed in the cylinder block is 2. The end bores 12 a 1 and 12 a 2 amongthe bores 12 that are arranged in series are bores situated on eitherend, and the intermediate bores 12 b 1 and 12 b 2 among the bores 12that are arranged in series are bores situated between the end bore 12 a1 situated on one end and the end bore 12 a 2 situated on the other end.An inter-bore wall 9 is formed between the end bore 12 a 1 and theintermediate bore 12 b 1, for example. Since heat is transmitted to theinter-bore wall 9 (that is situated between two cylinder bores) from twocylinder bores, the temperature of the inter-bore wall 9 increases ascompared with the walls other than the inter-bore wall 9. A cylinderbore-side wall surface 17 that defines the groove-like coolant passage14 defines a boundary 101 with respect to each bore. The wall surface ofthe groove-like coolant passage 14 that is situated on the side of thecylinder bores is referred to as “cylinder bore-side wall surface 17”,and the wall surface of the groove-like coolant passage 14 that issituated opposite to the cylinder bore-side wall surface 17 is referredto as “wall surface 18”.

Half of the groove-like coolant passage along the circumferentialdirection refers to half of the groove-like coolant passage when thegroove-like coolant passage is equally divided into two segments in thevertical direction along the direction in which the cylinder bores arearranged. In the example illustrated in FIG. 1, the cylinder bores arearranged in the direction that extends along the line Z-Z, and half ofthe groove-like coolant passage refers to half of the groove-likecoolant passage when the groove-like coolant passage is equally dividedinto two segments in the vertical direction along the direction thatextends along the line Z-Z. In the example illustrated in FIG. 1, halfof the groove-like coolant passage that is situated on the sideindicated by 20 a with respect to the line Z-Z is a groove-like coolantpassage 141 a that forms half of the groove-like coolant passage alongthe circumferential direction, and half of the groove-like coolantpassage that is situated on the side indicated by 20 b with respect tothe line Z-Z is a groove-like coolant passage 141 b that forms half ofthe groove-like coolant passage along the circumferential direction.Half of the groove-like coolant passage along the circumferentialdirection refers to the groove-like coolant passage 141 a or thegroove-like coolant passage 141 b.

Examples of the water jacket spacer that is disposed in the groove-likecoolant passage 14 provided to the cylinder block 11 illustrated in FIG.1 include the water jacket spacer 1 a (see (A) in FIG. 2) and the waterjacket spacer 1 b (see (B) in FIG. 2). The water jacket spacer 1 a isdisposed in the groove-like coolant passage 141 a (that forms half ofthe groove-like coolant passage 14 along the circumferential direction)that is provided to the cylinder block 11 illustrated in FIG. 1. Thewater jacket spacer 1 b is disposed in part of the groove-like coolantpassage 141 a (that forms half of the groove-like coolant passage 14along the circumferential direction) that is provided to the cylinderblock 11 illustrated in FIG. 1, and corresponds to the cylinder bores 12b 1 and 12 b 2. Further examples of the water jacket spacer that isdisposed in the groove-like coolant passage 14 provided to the cylinderblock 11 include a water jacket spacer that is disposed in thegroove-like coolant passage 141 b that forms half of the groove-likecoolant passage 14 along the circumferential direction, a water jacketspacer that is disposed in part of the groove-like coolant passage 141 aor 141 b (that forms half of the groove-like coolant passage 14), andcorresponds to the cylinder bores 12 a 1 and 12 b 1, a water jacketspacer that is disposed in part of the groove-like coolant passage 141 aor 141 b (that forms half of the groove-like coolant passage 14), andcorresponds to the cylinder bores 12 b 2 and 12 a 2, a water jacketspacer that is disposed in part of the groove-like coolant passage 141 aor 141 b (that forms half of the groove-like coolant passage 14), andcorresponds to the cylinder bores 12 a 1, 12 b 1, and 12 b 2, a waterjacket spacer that is disposed in part of the groove-like coolantpassage 141 a or 141 b (that forms half of the groove-like coolantpassage 14), and corresponds to the cylinder bores 12 b 1, 12 b 2, and12 a 2, a water jacket spacer that is disposed in part of thegroove-like coolant passage 141 a or 141 b (that forms half of thegroove-like coolant passage 14), and corresponds to the cylinder bore 12a 1, a water jacket spacer that is disposed in part of the groove-likecoolant passage 141 a or 141 b (that forms half of the groove-likecoolant passage 14), and corresponds to the cylinder bore 12 b 1, awater jacket spacer that is disposed in part of the groove-like coolantpassage 141 a or 141 b (that forms half of the groove-like coolantpassage 14), and corresponds to the cylinder bore 1262, a water jacketspacer that is disposed in part of the groove-like coolant passage 141 aor 141 b (that forms half of the groove-like coolant passage 14), andcorresponds to the cylinder bore 12 a 1, a water jacket spacer that isdisposed in the entirety or part of the groove-like coolant passage 141a, and part of the groove-like coolant passage 141 b, and the like.

The method for producing a water jacket spacer according to oneembodiment of the invention produces the water jacket spacer 1 a bysubjecting a synthetic resin to an injection molding process. Theinjection molding process that produces the water jacket spacer 1 autilizes an injection mold that forms a molding space that produces anintegrally molded product 10 a that includes at least two water jacketspacers 1 a, and a bridge 2, the two water jacket spacers 1 a beingprovided so that the inner sides thereof are situated opposite to eachother (see FIG. 9).

The injection molding process clamps an injection mold 30. Asillustrated in FIG. 3, the injection mold 30 includes a stationary mold31, slide molds (1) 32 a and 32 b, and a movable mold 33. The injectionmold 30 is clamped by a clamping step to form at least a molding space34 in which the integrally molded product 10 a is formed. The stationarymold 31, the slide molds (1) 32 a and 32 b, and the movable mold 33 areused to mold the integrally molded product 10 a. Note that FIGS. 3 to 6are views illustrating the state of the injection molding process at anend face position (at which a bridge is not formed) taken along a planethat is vertical to the direction in which the cylinder bores arearranged. FIGS. 7 and 8 are end views taken along the line Y-Yillustrated in FIG. 4. FIGS. 3 to 8 are schematic views illustrating thestate of the injection molding process that is implemented by the methodfor producing a water jacket spacer according to one embodiment of theinvention. Note that FIGS. 3 to 8 do not illustrate an example in whichthe molded product 10 a illustrated in FIG. 9 is produced by theinjection molding process.

As illustrated in FIGS. 4 and 7, the synthetic resin in a molten stateis injected into the molding space 34, and cooled and solidified whilekeeping pressure to form the integrally molded product 10 inside theinjection mold 30.

As illustrated in FIGS. 5, 6, and 8, the injection mold 30 is opened. Asillustrated in FIGS. 5 and 8, the movable mold 33 is moved in anupward-downward direction 35 with respect to the water jacket spacer(i.e., a direction 351 in which the movable mold 33 moves away from thestationary mold 31), and the slide molds (1) 32 a and 32 b are moved ina direction (38 a, 38 b) that is perpendicular to the direction in whichthe cylinder bores are arranged, and is also perpendicular to the movingdirection of the movable mold 33 (i.e., the slide molds (1) 32 a and 32b are moved away from the integrally molded product 10). The stationarymold 31 and the slide molds (1) 32 a and 32 b are thus removed from theintegrally molded product 10.

As illustrated in FIG. 6, the movable mold 33 is moved in theupward-downward direction 35 with respect to the water jacket spacer (inwhich the movable mold 33 moves away from the stationary mold 31) untila position at which the integrally molded product 10 can be removed fromthe movable mold 33, is reached.

The injection mold 30 is thus opened. After opening the injection mold30, the integrally molded product 10 that adheres to the movable mold 33is removed from the movable mold 33 (i.e., the integrally molded product10 is removed from the injection mold 30).

In FIGS. 4 to 6, the upward-downward direction with respect to the waterjacket spacer is indicated by reference numeral 35. In FIGS. 7 and 8,the direction in which the cylinder bores are arranged is indicated byreference numeral 37. In FIGS. 4 to 8, the direction that isperpendicular to the direction in which the cylinder bores are arranged,and is also perpendicular to the moving direction of the movable mold33, is indicated by reference numeral 36. In FIG. 5, the movingdirection of the movable mold 33 during the mold-opening step isindicated by reference numeral 351. The moving direction of the slidemold (1) 32 a and the moving direction of the slide mold (1) 32 b duringthe mold-opening step are indicated by reference numeral 38 a and 38 b,respectively.

As illustrated in FIG. 9, the integrally molded product 10 a that isformed inside the injection mold includes at least two water jacketspacers 1 a, and the bridge 2, the two water jacket spacers 1 a beingprovided so that the inner sides thereof are situated opposite to eachother, and the bridge 2 linking the inner sides of the two water jacketspacers 1 a. The bridge 2 included in the integrally molded product 10 aincludes an inter-bore bridge 2 a that links inter-bore parts 3 of thewater jacket spacers, and an end bridge 2 b that links ends 4 of thewater jacket spacers. When producing the integrally molded product 10 ausing the injection molding process, the molten resin may be injectedinto the injection mold from the end bridges 2 b, for example.

The method for producing a water jacket spacer according to oneembodiment of the invention includes subjecting a synthetic resin to aninjection molding process to produce a water jacket spacer, the waterjacket spacer being disposed in the entirety or part of a groove-likecoolant passage along a circumferential direction, the groove-likecoolant passage being provided to a cylinder block of an internalcombustion engine that has cylinder bores, the injection molding processincluding a clamping step that clamps an injection mold, an injectionstep that injects the synthetic resin in a molten state, asolidification step that cools and solidifies the synthetic resin whilekeeping pressure, a mold-opening step that opens the injection mold, andan ejection step that ejects an integrally molded product from theinjection mold, the injection mold including a stationary mold, amovable mold that moves in an upward-downward direction with respect tothe water jacket spacer, and at least one slide mold (1) that moves in adirection at an angle of +15° or less with respect to a direction thatis perpendicular to the direction in which the cylinder bores arearranged, and is perpendicular to a moving direction of the movablemold, and forming a molding space when clamped by the clamping step, themolding space producing the integrally molded product that includes atleast a first water jacket spacer, a second water jacket spacer, and abridge, the first water jacket spacer and the second water jacket spacerbeing provided so that the inner sides thereof are situated opposite toeach other, and the bridge linking the inner side or the end of thefirst water jacket spacer, and the inner side or the end of the secondwater jacket spacer, and the mold-opening step moving the movable moldin the upward-downward direction with respect to the water jacketspacer, and moving the slide mold (1) in a direction at an angle of ±15°or less with respect to the direction that is perpendicular to thedirection in which the cylinder bores are arranged, and is perpendicularto the moving direction of the movable mold, to open the injection mold.

The cylinder block in which the water jacket spacer produced using themethod for producing a water jacket spacer according to one embodimentof the invention is disposed, is an open-deck cylinder block in whichtwo or more cylinder bores are formed (arranged) in series. Theopen-deck cylinder block in which two cylinder bores are formed(arranged) in series, includes two end bores. The open-deck cylinderblock in which three or more cylinder bores are formed (arranged) inseries, includes two end bores, and one or more intermediate bores. Notethat the term “end bore” used herein refers to a cylinder bore among aplurality of cylinder bores arranged in series that is situated oneither end, and the term “intermediate bore” used herein refers to acylinder bore among a plurality of cylinder bores arranged in seriesthat is situated between other cylinder bores among the plurality ofcylinder bores.

The water jacket spacer produced using the method for producing a waterjacket spacer according to one embodiment of the invention is disposedin part of the groove-like coolant passage provided to the cylinderblock along the circumferential direction. Specifically, the waterjacket spacer produced using the method for producing a water jacketspacer according to one embodiment of the invention has a shape formedby one arc, or has a shape formed by two or more arcs that are linked toeach other (when viewed from above). The number of arcs included in thewater jacket spacer produced using the method for producing a waterjacket spacer according to one embodiment of the invention (when viewedfrom above), and the shape of the water jacket spacer produced using themethod for producing a water jacket spacer according to one embodimentof the invention (when viewed from above), are appropriately selectedtaking account of the number of cylinder bores formed in the cylinderblock, an area for which it is desired to change the flow of thecoolant, and the like. The molding space within the injection mold thatis used to mold the integrally molded product is designed taking accountof the desired shape of the water jacket spacer.

The method for producing a water jacket spacer according to oneembodiment of the invention produces the water jacket spacer bysubjecting the synthetic resin to the injection molding process. Theinjection molding process includes a clamping step that clamps theinjection mold, an injection step that injects the synthetic resin in amolten state into the molding space, a solidification step that coolsand solidifies the synthetic resin injected into the molding space whilekeeping pressure, a mold-opening step that opens the injection mold, andan ejection step that ejects the integrally molded product from theinjection mold.

The injection mold that is used for the injection molding process thatis implemented by the method for producing a water jacket spaceraccording to one embodiment of the invention is designed so that themolding space that is used to mold the integrally molded product isformed in the injection mold when the injection mold is clamped by theclamping step.

The injection mold that is used for the injection molding process thatis implemented by the method for producing a water jacket spaceraccording to one embodiment of the invention includes the stationarymold, the movable mold that moves in the upward-downward direction withrespect to the water jacket spacer so as to move away from thestationary mold, and one or two or more slide molds (1) that move in adirection at an angle of ±15° or less with respect to a direction thatis perpendicular to the direction in which the cylinder bores arearranged, and is perpendicular to the moving direction of the movablemold. Note that the inner side of the water jacket spacer refers to theside of the water jacket spacer that is situated opposite to thecylinder bore-side wall surface of the groove-like coolant passage, andthe outer side of the water jacket spacer refers to the side of thewater jacket spacer that is situated opposite to the wall surface of thegroove-like coolant passage that is situated opposite to the cylinderbore-side wall surface. The slide mold that moves in a direction at anangle of ±15° or less with respect to a direction that is perpendicularto the direction in which the cylinder bores are arranged, and isperpendicular to the moving direction of the movable mold, is referredto as “slide mold (1)”.

The slide mold (1) is used to form a part that is undercut with respectto the moving direction of the movable mold, and is not undercut withrespect to the moving direction of the slide mold (1) that moves in adirection at an angle of ±15° or less with respect to a direction thatis perpendicular to the direction in which the cylinder bores arearranged, and is perpendicular to the moving direction of the movablemold, on the outer side of the first water jacket spacer or the secondwater jacket spacer that forms the integrally molded product.

The injection mold that is used to produce the integrally molded productincludes the stationary mold, the movable mold that moves in theupward-downward direction with respect to the water jacket spacer so asto move away from the stationary mold, and at least one slide mold (1)that moves in a direction at an angle of ±15° or less with respect to adirection that is perpendicular to the direction in which the cylinderbores are arranged, and is perpendicular to the moving direction of themovable mold, and may optionally include a slide mold that moves in adirection at an angle of ±15° or less with respect to a direction thatis perpendicular to the direction in which the cylinder bores arearranged, and is perpendicular to the moving direction of the movablemold (hereinafter may be referred to as “slide mold (2)”), a slide moldthat moves in a direction at an angle of less than 90° with respect tothe direction in which the cylinder bores are arranged, and an angle of±15° or less with respect to a direction that is perpendicular to themoving direction of the movable mold (hereinafter may be referred to as“slide mold (3)”), and the like.

FIGS. 7 and 8 illustrate an example in which the injection mold that isused to produce the integrally molded product includes the stationarymold, the movable mold that moves in the upward-downward direction withrespect to the water jacket spacer, and two slide molds (1) that move ina direction at an angle of ±15° or less with respect to a direction thatis perpendicular to the direction in which the cylinder bores arearranged, and is perpendicular to the moving direction of the movablemold.

FIGS. 10 and 11 illustrate an example in which the injection mold thatis used to produce the integrally molded product includes the stationarymold (not illustrated in the drawings), a movable mold 331, slide molds(1) 321 a and 321 b, and slide molds (2) 341 a and 341 b. In themold-opening step, the movable mold 331 moves in the upward-downwarddirection with respect to the water jacket spacer (i.e., a directionperpendicular to the sheet in the example illustrated in FIGS. 10 and11), the slide molds (1) 321 a and 321 b move in a direction at an angleof ±15° or less with respect to a direction that is perpendicular to thedirection in which the cylinder bores are arranged, and is perpendicularto the moving direction of the movable mold (i.e., move in directions381 a and 381 b in which the slide molds (1) 321 a and 321 b move awayfrom an integrally molded product 10 b), and the slide molds (2) 341 aand 341 b move in a direction at an angle of ±15° or less with respectto the direction in which the cylinder bores are arranged, and adirection that is perpendicular to the moving direction of the movablemold (i.e., move in directions 391 a and 391 b in which the slide molds(2) 341 a and 341 b move away from the integrally molded product 10 b).The slide mold (2) is used to form a part that is undercut with respectto the movable mold, is undercut with respect to the slide mold (1) thatmoves in a direction at an angle of 15° or less with respect to adirection that is perpendicular to the direction in which the cylinderbores are arranged, and is perpendicular to the moving direction of themovable mold, and is not undercut with respect to the slide mold (2)that moves in a direction at an angle of ±15° or less with respect tothe direction in which the cylinder bores are arranged, and a directionthat is perpendicular to the moving direction of the movable mold, onthe outer side of the first water jacket spacer or the second waterjacket spacer that forms the integrally molded product. Specifically,the injection mold that is used to produce the integrally molded productmay include the stationary mold, the movable mold that moves in theupward-downward direction with respect to the water jacket spacer, twoslide molds (1) that move in a direction at an angle of ±15° or lesswith respect to a direction that is perpendicular to the direction inwhich the cylinder bores are arranged, and is perpendicular to themoving direction of the movable mold, and two slide molds (2) that movein a direction at an angle of ±15° or less with respect to the directionin which the cylinder bores are arranged, and a direction that isperpendicular to the moving direction of the movable mold.

FIGS. 12 and 13 illustrate an example in which the injection mold thatis used to produce the integrally molded product includes the stationarymold (not illustrated in the drawings), a movable mold 332, slide molds(1) 322 a and 322 b, and a slide mold (2) 342 a. In the mold-openingstep, the movable mold 332 moves in the upward-downward direction withrespect to the water jacket spacer (i.e., a direction perpendicular tothe sheet in the example illustrated in FIGS. 12 and 13), the slidemolds (1) 322 a and 322 b move in a direction at an angle of ±15l orless with respect to a direction that is perpendicular to the directionin which the cylinder bores are arranged, and is perpendicular to themoving direction of the movable mold (i.e., move in directions 382 a and382 b in which the slide molds (1) 322 a and 322 b move away from anintegrally molded product 10 c), and the slide mold (2) 342 a moves in adirection at an angle of ±15° or less with respect to the direction inwhich the cylinder bores are arranged, and a direction that isperpendicular to the moving direction of the movable mold (i.e., move ina directions 392 a in which the slide mold (2) 342 a moves away from theintegrally molded product 10 c). Specifically, the injection mold thatis used to produce the integrally molded product may include thestationary mold, the movable mold that moves in the upward-downwarddirection with respect to the water jacket spacer, two slide molds (1)that move in a direction at an angle of ±15° or less with respect to adirection that is perpendicular to the direction in which the cylinderbores are arranged, and is perpendicular to the moving direction of themovable mold, and one slide mold (2) that moves in a direction at anangle of ±15° or less with respect to the direction in which thecylinder bores are arranged, and a direction that is perpendicular tothe moving direction of the movable mold.

FIGS. 14 and 15 illustrate an example in which the injection mold thatis used to produce the integrally molded product includes the stationarymold (not illustrated in the drawings), a movable mold 333, and slidemolds (1) 323 a and 323 b. In the mold-opening step, the movable mold333 moves in the upward-downward direction with respect to the waterjacket spacer (i.e., a direction perpendicular to the sheet in theexample illustrated in FIGS. 14 and 15), and the slide molds (1) 323 aand 323 b move in a direction at an angle of ±15° or less with respectto a direction that is perpendicular to the direction in which thecylinder bores are arranged, and is perpendicular to the movingdirection of the movable mold (i.e., move in directions 383 a and 383 bin which the slide molds (1) 323 a and 323 b move away from anintegrally molded product 10 d). In the example illustrated in FIGS. 14and 15, the movable mold is situated on the inner side and the outerside of the water jacket spacer. When a part that is undercut withrespect to the movable mold is not provided on the outer side of thewater jacket spacer, the movable mold that is situated on the inner sideand the outer side of the water jacket spacer may be used. Specifically,the injection mold that is used to produce the integrally molded productmay include the stationary mold, the movable mold that moves in theupward-downward direction with respect to the water jacket spacer, andtwo slide molds (1) that move in a direction at an angle of ±15° or lesswith respect to a direction that is perpendicular to the direction inwhich the cylinder bores are arranged, and is perpendicular to themoving direction of the movable mold, and the movable mold may besituated on the inner side and the outer side of the water jacketspacer.

FIGS. 16 and 17 illustrate an example in which the injection mold thatis used to produce the integrally molded product includes the stationarymold (not illustrated in the drawings), a movable mold 334, and slidemolds (1) 324 a and 324 b. In the mold-opening step, the movable mold334 moves in the upward-downward direction with respect to the waterjacket spacer (i.e., a direction perpendicular to the sheet in theexample illustrated in FIGS. 16 and 17), and the slide molds (1) 324 aand 324 b move in a direction at an angle of ±15° or less with respectto a direction that is perpendicular to the direction in which thecylinder bores are arranged, and is perpendicular to the movingdirection of the movable mold (i.e., move in directions 384 a and 384 bin which the slide molds (1) 324 a and 324 b move away from anintegrally molded product 10 e). In the example illustrated in FIGS. 16and 17, the movable mold 334 is situated on the inner side and the outerside of the water jacket spacer. Specifically, the injection mold thatis used to produce the integrally molded product may include thestationary mold, the movable mold that moves in the upward-downwarddirection with respect to the water jacket spacer, and two slide molds(1) that move in a direction at an angle of ±15° or less with respect toa direction that is perpendicular to the direction in which the cylinderbores are arranged, and is perpendicular to the moving direction of themovable mold, and the movable mold may be situated on the inner side andthe outer side of the water jacket spacer.

FIGS. 18 and 19 illustrate an example in which the injection mold thatis used to produce the integrally molded product includes the stationarymold (not illustrated in the drawings), a movable mold 335, and a slidemold (1) 325 a. In the mold-opening step, the movable mold 335 moves inthe upward-downward direction with respect to the water jacket spacer(i.e., a direction perpendicular to the sheet in the example illustratedin FIGS. 18 and 19), and the slide mold (1) 325 a moves in a directionat an angle of 15° or less with respect to a direction that isperpendicular to the direction in which the cylinder bores are arranged,and is perpendicular to the moving direction of the movable mold (i.e.,move in a direction 385 in which the slide mold (1) 325 a moves awayfrom an integrally molded product 10 f). In the example illustrated inFIGS. 18 and 19, the movable mold 335 is situated on the inner side andthe outer side of the water jacket spacer (the inner side of the waterjacket spacers, and the outer side of one of the water jacket spacers).When a part that is undercut with respect to the movable mold is notprovided on the outer side of one of the water jacket spacers, themovable mold that is situated on the inner side and the outer side ofthe water jacket spacer may be used. In this case, one slide mold (1)can be used with respect to the water jacket spacer for which a partthat is undercut with respect to the movable mold, and is not undercutwith respect to the slide mold (1) that moves in a direction at an angleof ±15° or less with respect to a direction that is perpendicular to thedirection in which the cylinder bores are arranged, and is perpendicularto the moving direction of the movable mold, is formed. Specifically,the injection mold that is used to produce the integrally molded productmay include the stationary mold, the movable mold that moves in theupward-downward direction with respect to the water jacket spacer, andone slide mold (1) that moves in a direction at an angle of ±15° or lesswith respect to a direction that is perpendicular to the direction inwhich the cylinder bores are arranged, and is perpendicular to themoving direction of the movable mold, and the movable mold may besituated on the inner side and the outer side of the water jacketspacer.

In the examples illustrated in FIGS. 14 to 17, the movable mold issituated on the outer side of the water jacket spacer. In the examplesillustrated in FIGS. 14 to 17, an adhesion-to-slide phenomenon in whichthe water jacket spacer adheres to the slide mold (1) and moves togetherwith the slide mold (1) does not occur, but a member that is formedoutside the water jacket spacer adheres to the slide mold (1), and isstrongly pulled by the slide mold (1). In FIGS. 10 to 19, the directionin which the cylinder bores are arranged is indicated by referencenumeral 37, and a direction that is perpendicular to the direction inwhich the cylinder bores are arranged, and is also perpendicular to themoving direction of the movable mold is indicated by reference numeral36.

FIG. 20 illustrates an example in which the injection mold that is usedto produce the integrally molded product includes a stationary mold 316,a movable mold 336, and slide molds (1) 326 a and 326 b. In themold-opening step, the movable mold 336 moves in the upward-downwarddirection 35 with respect to the water jacket spacer, and the slide mold(1) 326 a and 326 b move in a direction at an angle of ±15° or less withrespect to a direction that is perpendicular to the direction in whichthe cylinder bores are arranged, and is perpendicular to the movingdirection of the movable mold (i.e., move in directions 386 a and 386 bin which the slide molds (1) 326 a and 326 b move away from anintegrally molded product 10 g). In the example illustrated in FIG. 20,the slide mold (1) moves in a direction at an angle of 15° or less withrespect to a direction that is perpendicular to the moving direction ofthe movable mold, instead of moving in a direction perpendicular to themoving direction of the movable mold.

As described above, the injection mold that is used for the injectionmolding process that is implemented by the method for producing a waterjacket spacer according to one embodiment of the invention includes thestationary mold, the movable mold that moves in the upward-downwarddirection with respect to the water jacket spacer, and at least oneslide mold (1) that moves in a direction at an angle of ±15° or lesswith respect to a direction that is perpendicular to the direction inwhich the cylinder bores are arranged, and is perpendicular to themoving direction of the movable mold. A part of the first water jacketspacer and the second water jacket spacer that form the integrallymolded product that is molded using the stationary mold and the movablemold is appropriately selected taking account of the first water jacketspacer and the second water jacket spacer that form the integrallymolded product (i.e., a part of the first water jacket spacer and thesecond water jacket spacer that is undercut with respect to thestationary mold or the movable mold is formed). The injection mold thatis used for the injection molding process that is implemented by themethod for producing a water jacket spacer according to one embodimentof the invention preferably includes one or two slide molds (1)(particularly preferably two slide molds (1)). The number of slide molds(1) is appropriately selected taking account of the first water jacketspacer and the second water jacket spacer that form the integrallymolded product (i.e., a part of the first water jacket spacer and thesecond water jacket spacer that is undercut with respect to the movablemold, and is not undercut with respect to the slide mold (1)). Theinjection mold that is used for the injection molding process that isimplemented by the method for producing a water jacket spacer accordingto one embodiment of the invention may optionally include, in additionto the stationary mold, the movable mold, and the slide mold (1), theslide mold (2) that moves in a direction at an angle of ±15° or lesswith respect to the direction in which the cylinder bores are arranged,and a direction that is perpendicular to the moving direction of themovable mold, the slide mold (3) that moves in a direction at an angleof less than 90° with respect to the direction in which the cylinderbores are arranged, and an angle of ±15° or less with respect to adirection that is perpendicular to the moving direction of the movablemold, and the like. Whether or not to provide the slide mold (1) and theslide mold (3) to the injection mold, and a part of the first waterjacket spacer and the second water jacket spacer that form theintegrally molded product that is molded using the slide mold (1) andthe slide mold (3), are appropriately selected taking account of thefirst water jacket spacer and the second water jacket spacer that formthe integrally molded product (i.e., whether or not to provide the firstwater jacket spacer and the second water jacket spacer with a part thatis undercut with respect to the movable mold, is undercut with respectto the slide mold (1), and is not undercut with respect to the slidemold (1) or the slide mold (3), and an area in which such a part isformed).

The slide mold (1) that is included in the injection mold that is usedfor the injection molding process that is implemented by the method forproducing a water jacket spacer according to one embodiment of theinvention moves in a direction at an angle of ±15° or less with respectto a direction that is perpendicular to the direction in which thecylinder bores are arranged, and is perpendicular to the movingdirection of the movable mold. Specifically, the slide mold (1) may movein a direction that is perpendicular to the direction in which thecylinder bores are arranged, and is perpendicular to the movingdirection of the movable mold, or may move in a direction at an angle of±15° or less with respect to a direction that is perpendicular to thedirection in which the cylinder bores are arranged, and is perpendicularto the moving direction of the movable mold.

Although FIG. 9 illustrates an example in which an additional member isnot formed outside the water jacket spacer 1 a for convenience ofexplanation with respect to the integrally molded product, a part thatis undercut with respect to the movable mold is formed on the outer sideof the actual water jacket spacer (see water jacket spacers 1 j, 1 k,and 1 m illustrated in FIGS. 21 and 22). Although FIGS. 3 to 8 and FIGS.10 to 20 illustrate an example in which a part that is undercut withrespect to the movable mold is not formed on the outer side of the waterjacket spacer for convenience of explanation, a part that is undercutwith respect to the movable mold is formed on the outer side of theactual water jacket spacer. Therefore, the injection molding processcannot be implemented using only the stationary mold and the movablemold, and it is necessary to use the slide mold (1), or the slide mold(1) and the slide mold (2) or (3), for example.

In the clamping step, the injection mold is clamped to form the moldingspace for molding the integrally molded product in the injection mold.In the injection step, the synthetic resin in a molten state is injectedinto the molding space formed in the injection mold to fill the moldingspace with the synthetic resin. In the solidification step, thesynthetic resin that has been injected into the molding space in theinjection step is cooled and solidified while keeping pressure to formthe integrally molded product in the molding space formed in theinjection mold.

In the mold-opening step, the injection mold is opened. In themold-opening step, the movable mold is moved in the upward-downwarddirection with respect to the water jacket spacer so as to move awayfrom the stationary mold, and the slide mold (1) is moved in a directionat an angle of ±15° or less with respect to a direction that isperpendicular to the direction in which the cylinder bores are arranged,and is perpendicular to the moving direction of the movable mold so asto move away from the integrally molded product. The stationary mold andthe slide mold (1) are thus removed from the integrally molded product.The movable mold is moved in the upward-downward direction with respectto the water jacket spacer (in which the movable mold moves away fromthe stationary mold) until a position at which the integrally moldedproduct can be removed from the movable mold, is reached. The injectionmold is thus opened.

In the ejection step, the integrally molded product that adheres to thestationary mold is removed from the stationary mold after performing themold-opening step to eject the integrally molded product from theinjection mold.

The molding space that is formed in the injection mold by the clampingstep has a shape such that the integrally molded product described belowis formed. Specifically, the method for producing a water jacket spaceraccording to one embodiment of the invention utilizes the injection moldin which the molding space is formed by the clamping step so as to havea shape such that the integrally molded product described below isformed.

The integrally molded product that is formed in the injection mold byimplementing the method for producing a water jacket spacer according toone embodiment of the invention includes at least the first water jacketspacer, the second water jacket spacer, and the bridge that links theinner side or the end of the first water jacket spacer, and the innerside or the end of the second water jacket spacer. The first waterjacket spacer and the second water jacket spacer may be provided with aninsulation rubber member and an additional member (on the inner side),and disposed in the groove-like coolant passage, or may be disposed inthe groove-like coolant passage without being provided with aninsulation rubber member and the like (on the inner side).

The first water jacket spacer and the second water jacket spacer thatform the integrally molded product may be identical to or different fromeach other as to the shape. The first water jacket spacer and the secondwater jacket spacer that form the integrally molded product may bedisposed in the groove-like coolant passage provided to an identicalcylinder block, or may be disposed in the groove-like coolant passageprovided to a different cylinder block. In the example illustrated inFIG. 21, an integrally molded product 10 j includes two water jacketspacers 1 j having an identical shape. The two water jacket spacers 1 jincluded in the integrally molded product 10 j are disposed in thegroove-like coolant passage provided to a different cylinder block. Inthe example illustrated in FIG. 22, an integrally molded product 10 kincludes water jacket spacers 1 k and 1 m having a different shape. Theintegrally molded product 10 k includes the water jacket spacer 1 k thatis disposed in half of the groove-like coolant passage provided to thecylinder block, and the water jacket spacer 1 m that is disposed in theother half of the groove-like coolant passage provided to the cylinderblock. In the example illustrated in FIG. 23, an integrally moldedproduct 10 h includes water jacket spacers 1 p and 1 q that differ inthe number of bore-covering parts. The number of bore-covering parts ofthe water jacket spacer 1 p is 4, and the number of bore-covering partsof the water jacket spacer 1 q is 3. In the example illustrated in FIG.27, an integrally molded product 10 n includes two water jacket spacers1 u that are disposed in half of the groove-like coolant passage, andalso disposed in part of the other half of the groove-like coolantpassage. The water jacket spacers 1 u illustrated in FIG. 27 aredisposed in half of the groove-like coolant passage, and also disposedin part of the other half of the groove-like coolant passage.

The integrally molded product includes one or more pairs of first waterjacket spacer and second water jacket spacer. When the number ofbore-covering parts of the first water jacket spacer and the secondwater jacket spacer that form the integrally molded product is large, avery large injection mold is required when the integrally molded productthat includes two or more pairs of first water jacket spacer and secondwater jacket spacer is formed. In such a case, it is preferable that theintegrally molded product include one pair of first water jacket spacerand second water jacket spacer. When the number of bore-covering partsof the first water jacket spacer and the second water jacket spacer thatform the integrally molded product is small, a large injection mold isnot required even when the integrally molded product that includes twoor more pairs of first water jacket spacer and second water jacketspacer is formed. The production efficiency increases as the number ofpairs of first water jacket spacer and second water jacket spacerincluded in the integrally molded product increases. Therefore, it ispreferable that the integrally molded product include two or more pairsof first water jacket spacer and second water jacket spacer when thenumber of bore-covering parts of the first water jacket spacer and thesecond water jacket spacer that form the integrally molded product issmall. In the example illustrated in FIG. 24, an integrally moldedproduct 10 i includes first water jacket spacers 1 r 1 and 1 r 2, andsecond water jacket spacers 1 s 1 and 1 s 2. The first water jacketspacers 1 r 1 and 1 r 2 are linked through a link 23, and the secondwater jacket spacers 1 s 1 and 1 s 2 are linked through a link 23.Specifically, the integrally molded product includes two pairs of firstwater jacket spacer and second water jacket spacer.

The first water jacket spacer and the second water jacket spacer thatform the integrally molded product have a shape such that the firstwater jacket spacer and the second water jacket spacer are disposed inpart of the groove-like coolant passage. The water jacket spacer mayhave a shape such that the water jacket spacer is disposed in half ofthe groove-like coolant passage (e.g., the water jacket spacer 1 aillustrated in FIG. 2), or may have a shape such that the water jacketspacer is disposed in part of half of the groove-like coolant passage(e.g., the water jacket spacer 1 b illustrated in FIG. 2), or may have ashape such that the water jacket spacer is disposed in half of thegroove-like coolant passage, and part of the other half of thegroove-like coolant passage (e.g., the water jacket spacer 1 uillustrated in FIG. 27), or may have a shape such that the water jacketspacer is disposed in part of half of the groove-like coolant passage,and part of the other half of the groove-like coolant passage. The firstwater jacket spacer and the second water jacket spacer that form theintegrally molded product may have a shape formed by one arc, or mayhave a shape formed by two or more arcs that are linked to each other(when viewed from above).

The first water jacket spacer and the second water jacket spacer thatform the integrally molded product may include a coolant flow changemember 21 that changes the flow of the coolant so that the coolantsupplied to the lower part of the groove-like coolant passage flowsthrough the upper part of the groove-like coolant passage, a coolantflow prevention member 22 that prevents a situation in which the coolantsupplied to the lower part of the groove-like coolant passage flows fromthe lower side of the water jacket spacer into the inner side of thewater jacket spacer, and the like. The first water jacket spacer and thesecond water jacket spacer that form the integrally molded product mayinclude a member that prevents upward displacement, such as a cylinderhead contact member that is provided on the water jacket spacers, andcomes in contact with a cylinder head or a cylinder head gasket. Thefirst water jacket spacer and the second water jacket spacer that formthe integrally molded product may also include a member that adjusts theflow of the coolant.

An adhesion-to-slide phenomenon can be prevented by providing one bridgeto the integrally molded product so that the inner side or the end ofthe first water jacket spacer, and the inner side or the end of thesecond water jacket spacer are linked through the bridge.

The position of the integrally molded product at which the bridge isformed is not particularly limited as long as an adhesion-to-slidephenomenon can be prevented. The bridge may be formed at a position atwhich the end of the first water jacket spacer and the end of the secondwater jacket spacer are linked, or may be formed at a position at whichthe inner side of the inter-bore part of the first water jacket spacerand the inner side of the inter-bore part of the second water jacketspacer are linked, or may be formed at a position at which the innerside of the bore-covering part of the first water jacket spacer and theinner side of the bore-covering part of the second water jacket spacerare linked, or may be formed at a position at which the inner side ofthe inter-bore part of the first water jacket spacer and the inner sideof the bore-covering part of the second water jacket spacer are linked.Note that the inter-bore part of the water jacket spacer refers to apart of the water jacket spacer that is situated opposite to theinter-bore boundary of the cylinder bore-side wall surface of thegroove-like coolant passage, and the vicinity thereof. Since thecylinder bore-side wall surface of the groove-like coolant passage thatcorresponds to the side of the inter-bore wall corresponds to theinter-bore boundary of the cylinder bore-side wall surface of thegroove-like coolant passage, and the vicinity thereof, a part of thewater jacket spacer that is situated opposite to the inter-bore boundaryof the cylinder bore-side wall surface of the groove-like coolantpassage, and the vicinity thereof, is referred to as the inter-bore partof the water jacket spacer. In the example illustrated in FIG. 9, theinter-bore part of the water jacket spacer is indicated by referencenumeral 3. The bore-covering part of the water jacket spacer refers to apart of the water jacket spacer that is situated opposite to thebore-covering part of the cylinder bore-side wall surface of thegroove-like coolant passage, and is in the shape of an arc when viewedfrom above. In the example illustrated in FIG. 9, the bore-covering partof the water jacket spacer is indicated by reference numeral 8.

When the number of bore-covering parts of the first water jacket spaceris equal to the number of bore-covering parts of the second water jacketspacer (case (I)), the bridge may be formed at the positions describedbelow with respect to the integrally molded product (see (i) to (iv)).

(i) The bridge may be formed at a position at which one end of the firstwater jacket spacer and one end of the second water jacket spacer arelinked, and a position at which the other end of the first water jacketspacer and the other end of the second water jacket spacer are linked.(ii) The bridge may be formed at one position at which the inner side ofthe inter-bore part of the first water jacket spacer and the inner sideof the inter-bore part of the second water jacket spacer are linked.(iii) The bridge may be formed at two or more positions at which theinner side of the inter-bore part of the first water jacket spacer andthe inner side of the inter-bore part of the second water jacket spacerare linked.(iv) The bridge may be formed at a position at which one end of thefirst water jacket spacer and one end of the second water jacket spacerare linked, a position at which the other end of the first water jacketspacer and the other end of the second water jacket spacer are linked,and one or more positions at which the inner side of the inter-bore partof the first water jacket spacer and the inner side of the inter-borepart of the second water jacket spacer are linked.

When the number of bore-covering parts of the first water jacket spacerdiffers from the number of bore-covering parts of the second waterjacket spacer (case (II)), the bridge may be formed at the positionsdescribed below with respect to the integrally molded product (see (i)to (iv)).

(i) The bridge may be formed at a position at which one end of the firstwater jacket spacer or the second water jacket spacer, whichever issmaller with respect to the number of bore-covering parts, and one endof the first water jacket spacer or the second water jacket spacer,whichever is larger with respect to the number of bore-covering parts,are linked, and a position at which the other end of the first waterjacket spacer or the second water jacket spacer, whichever is smallerwith respect to the number of bore-covering parts, and the inner side ofthe inter-bore part of the first water jacket spacer or the second waterjacket spacer, whichever is larger with respect to the number ofbore-covering parts, are linked.(ii) The bridge may be formed at a position at which the inner side ofthe inter-bore part of the first water jacket spacer or the second waterjacket spacer, whichever is smaller with respect to the number ofbore-covering parts, and the inner side of the inter-bore part of thefirst water jacket spacer or the second water jacket spacer, whicheveris larger with respect to the number of bore-covering parts, are linked.(iii) The bridge may be formed at two or more positions at which theinner side of the inter-bore part of the first water jacket spacer orthe second water jacket spacer, whichever is smaller with respect to thenumber of bore-covering parts, and the inner side of the inter-bore partof the first water jacket spacer or the second water jacket spacer,whichever is larger with respect to the number of bore-covering parts,are linked.(iv) The bridge may be formed at a position at which one end of thefirst water jacket spacer or the second water jacket spacer, whicheveris smaller with respect to the number of bore-covering parts, and oneend of the first water jacket spacer or the second water jacket spacer,whichever is larger with respect to the number of bore-covering parts,are linked, a position at which the other end of the first water jacketspacer or the second water jacket spacer, whichever is smaller withrespect to the number of bore-covering parts, and the inner side of theinter-bore part of the first water jacket spacer or the second waterjacket spacer, whichever is larger with respect to the number ofbore-covering parts, are linked, and one or more positions at which theinner side of the inter-bore part of the first water jacket spacer orthe second water jacket spacer, whichever is smaller with respect to thenumber of bore-covering parts, and the inner side of the inter-bore partof the first water jacket spacer or the second water jacket spacer,whichever is larger with respect to the number of bore-covering parts,are linked.

In the example (i) that falls under the case (I), the integrally moldedproduct includes an end bridge that links one end of the first waterjacket spacer and one end of the second water jacket spacer, and an endbridge that links the other end of the first water jacket spacer and theother end of the second water jacket spacer. In the example (ii) thatfalls under the case (I), the integrally molded product includes oneinter-bore bridge that links the inner side of the inter-bore part ofthe first water jacket spacer and the inner side of the inter-bore partof the second water jacket spacer. In the example (iii) that falls underthe case (I), the integrally molded product includes two or moreinter-bore bridges that link the inner side of the inter-bore part ofthe first water jacket spacer and the inner side of the inter-bore partof the second water jacket spacer. In the example (iv) that falls underthe case (I), the integrally molded product includes an end bridge thatlinks one end of the first water jacket spacer and one end of the secondwater jacket spacer, an end bridge that links the other end of the firstwater jacket spacer and the other end of the second water jacket spacer,and one or more inter-bore bridges that link the inner side of theinter-bore part of the first water jacket spacer and the inner side ofthe inter-bore part of the second water jacket spacer.

In the example (i) that falls under the case (II), the integrally moldedproduct includes an end bridge that links one end of the first waterjacket spacer or the second water jacket spacer, whichever is smallerwith respect to the number of bore-covering parts, and one end of thefirst water jacket spacer or the second water jacket spacer, whicheveris larger with respect to the number of bore-covering parts, and aninter-bore bridge that links the other end of the first water jacketspacer or the second water jacket spacer, whichever is smaller withrespect to the number of bore-covering parts, and the inner side of theinter-bore part of the first water jacket spacer or the second waterjacket spacer, whichever is larger with respect to the number ofbore-covering parts. In the example (ii) that falls under the case (II),the integrally molded product includes one inter-bore bridge that linksthe inner side of the inter-bore part of the first water jacket spaceror the second water jacket spacer, whichever is smaller with respect tothe number of bore-covering parts, and the inner side of the inter-borepart of the first water jacket spacer or the second water jacket spacer,whichever is larger with respect to the number of bore-covering parts.In the example (iii) that falls under the case (II), the integrallymolded product includes two or more inter-bore bridges that link theinner side of the inter-bore part of the first water jacket spacer orthe second water jacket spacer, whichever is smaller with respect to thenumber of bore-covering parts, and the inner side of the inter-bore partof the first water jacket spacer or the second water jacket spacer,whichever is larger with respect to the number of bore-covering parts.In the example (iv) that falls under the case (II), the integrallymolded product includes an end bridge that links one end of the firstwater jacket spacer or the second water jacket spacer, whichever issmaller with respect to the number of bore-covering parts, and one endof the first water jacket spacer or the second water jacket spacer,whichever is larger with respect to the number of bore-covering parts,an inter-bore bridge that links the other end of the first water jacketspacer or the second water jacket spacer, whichever is smaller withrespect to the number of bore-covering parts, and the inner side of theinter-bore part of the first water jacket spacer or the second waterjacket spacer, whichever is larger with respect to the number ofbore-covering parts, and one or more inter-bore bridges that link theinner side of the inter-bore part of the first water jacket spacer orthe second water jacket spacer, whichever is smaller with respect to thenumber of bore-covering parts, and the inner side of the inter-bore partof the first water jacket spacer or the second water jacket spacer,whichever is larger with respect to the number of bore-covering parts.

The integrally molded product may include a bridge that links anarc-shaped center area of the inner side of the bore-covering part ofthe first water jacket spacer and an arc-shaped center area of the innerside of the bore-covering part of the second water jacket spacer. Notethat the arc-shaped center area of the inner side of the bore-coveringpart refers to an area that is situated on the inner side of the centerarea of the arc-shaped bore-covering part when viewed from above.

The positions of the bridge (that is provided to the integrally moldedproduct) in the upward-downward direction is appropriately selectedtaking account of the shape of the first water jacket spacer and thesecond water jacket spacer.

Examples of the bridge that is provided to the integrally molded productinclude a bridge 2 a (see (A) in FIG. 25) that includes one linear (whenviewed from above) bridge main body 2 a 1, and bridge thin parts 2 a 2that link either end of the bridge main body 2 a 1 and the inner side ofthe inter-bore part of the water jacket spacer, a bridge 2 c (see (B) inFIG. 25) that includes only one linear (when viewed from above) bridgemain body, a bridge 2 d or 2 e (see (C) or (D) in FIG. 25) that includesa bridge main body 2 d 1 or 2 e 1 that includes one linear section thatextends in the longitudinal direction in which the water jacket spacerextends (when viewed from above), and a branch section that branchesfrom the section that extends in the longitudinal direction, and extendstoward the inner side of the water jacket spacer, and a bridge thin part2 d 2 or 2 e 2 that links the end of the branch section and the innerside of the water jacket spacer, a bridge that includes one linearsection that extends in the longitudinal direction in which the waterjacket spacer extends (when viewed from above), and a branch sectionthat branches from the section that extends in the longitudinaldirection, and extends toward the inner side of the water jacket spacer,and the like. The bridge 2 d and 2 e (see (C) and (D) in FIG. 25) areformed as a bridge that links the inner side of the first water jacketspacer and the inner side of the second water jacket spacer when thefirst water jacket spacer and the second water jacket spacer that faceeach other are disposed so that the inter-bore parts are shifted fromeach other (i.e., when the first water jacket spacer and the secondwater jacket spacer are disposed so that the inter-bore part of one ofthe first water jacket spacer and the second water jacket spacer facesthe area between the inter-bore parts of the other of the first waterjacket spacer and the second water jacket spacer (e.g., an area aroundthe center of each bore)). Note that the shape of the bridge is notlimited to those described above.

The integrally molded product may include an inter-bridge bridge 5 thatincludes an end bridge 2 b that is provided on each end of a first waterjacket spacer 1 t and a second water jacket spacer 1 t, and one or moreinter-bore bridges 2 a, and links a center area of the inter-bore bridgeand a center area of the end bridge that is situated adjacent to theinter-bore bridge, or links center areas of the inter-bore bridges thatare situated adjacent to each other (see an integrally molded product 10m illustrated in FIG. 26).

The injection mold that is used for the injection molding process may beplaced in an arbitrary way. The injection mold is normally placed sothat the movable mold moves in the vertical direction, or moves in thehorizontal direction.

The molded product obtained by the injection molding process normallyincludes a main body, a spool that serves as a molten resin passage thatextends from a nozzle of an injection molding machine to a runner, arunner that serves as an intermediate molten resin passage that extendsfrom the spool to a gate, and a gate that serves as an inlet throughwhich a molten resin flows from the runner into the molding space (mainbody molding space). The integrally molded product produced using themethod for producing a water jacket spacer according to one embodimentof the invention may further include a spool, a runner, and a gate. Theintegrally molded product may be configured so that the bridge main bodyor the inter-bridge bridge serves as a runner, and the bridge thin partserves as a gate. When implementing the method for producing a waterjacket spacer according to one embodiment of the invention, the positionat which the molten resin is injected into the injection mold isappropriately selected taking account of the shape of the integrallymolded product, the shape of the injection mold, and the like. Forexample, the molten resin may be injected from the position of thebridge situated at each end, or may be injected from the position of thewater jacket spacer, or may be injected from the center position of theinter-bridge bridge.

The synthetic resin that is subjected to the injection molding processthat is implemented by the method for producing a water jacket spaceraccording to one embodiment of the invention to form the integrallymolded product is not particularly limited. A resin that is normallyused as a material for producing a water jacket spacer that is disposedin the groove-like coolant passage provided to the cylinder block may beused as the synthetic resin.

When implementing the method for producing a water jacket spaceraccording to one embodiment of the invention, the integrally moldedproduct is ejected by the ejection step, and sufficiently cooled andsolidified, and the bridge is separated (cut) from the first waterjacket spacer and the second water jacket spacer. When the integrallymolded product includes a part (e.g., spool, runner, or gate) that isformed together with the main body by injection molding, and isunnecessary for the water jacket spacer, such a part is also separated(cut) from the water jacket spacer.

According to the method for producing a water jacket spacer according toone embodiment of the invention, since the integrally molded productthat is formed inside the injection mold by means of injection moldingincludes the bridge that links the inner side of the first water jacketspacer and the inner side of the second water jacket spacer, it ispossible to prevent the occurrence of an adhesion-to-slide phenomenon inwhich the first water jacket spacer or the second water jacket spaceradheres to the slide mold when the slide mold (1) moves in a directionat an angle of ±15° or less with respect to a direction that isperpendicular to a direction in which the cylinder bores are arranged,and is perpendicular to the moving direction of the movable mold, so asto move away from the integrally molded product, when the injection moldis opened.

INDUSTRIAL APPLICABILITY

The embodiments of the invention can prevent the occurrence of anadhesion-to-slide phenomenon during injection molding, and canefficiently produce a water jacket spacer having a shape thatcorresponds to part of the groove-like coolant passage along thecircumferential direction by means of injection molding.

REFERENCE SIGNS LIST

-   1 a, 1 g 1, 1 g 2, 1 j, 1 k, 1 m, 1 p, 1 q, 1 r 1, 1 r 2, 1 s 1, 1 s    2, 1 t, 1 u: Water jacket spacer-   2: Bridge-   2 a: Inter-bore bridge-   2 a: Bridge main body-   2 a 2: Bridge thin part-   2 b: End bridge-   3: Inter-bore part of water jacket spacer-   4: End of water jacket spacer-   5: Inter-bridge bridge-   8: Bore-covering part of water jacket spacer-   9: Inter-bore wall-   10, 10 a, 10 b, 10 c, 10 d, 10 e, 10 f, 10 g, 10 h, 10 i, 10 j, 10    k, 10 m: Integrally molded product-   11: Cylinder block-   12: Bore-   12 a 1, 12 a 2: End bore-   12 b 1, 12 b 2: Intermediate bore-   13: Cylinder bore wall-   14: Groove-like coolant passage-   15: Coolant inlet-   16: Coolant outlet-   17: Cylinder bore-side wall surface of groove-like coolant passage-   18: Wall surface of groove-like coolant passage opposite to cylinder    bore-side wall surface-   20 a, 20 b: One side of groove-like coolant passage-   21: Coolant flow change member-   22: Coolant flow prevention member-   30: Injection mold-   31, 316: Stationary mold-   32 a, 32 b, 321 a, 321 b, 322 a, 322 b, 323 a, 323 b, 324 a, 324 b,    325 a: Slide mold (1)-   33, 331, 332, 333, 334, 335, 336: Movable mold-   34: Molding space for molding integrally molded product-   35: Upward-downward direction with respect to water jacket spacer-   36: Direction that is perpendicular to upward-downward direction    with respect to water jacket spacer and is perpendicular to moving    direction of movable mold-   37: Direction in which cylinder bores are arranged-   38 a, 38 b, 381 a, 381 b, 382 a, 382 b, 383 a, 383 b, 384 a, 384 b,    385, 386, 386 b: Moving direction of slide mold (1) during    mold-opening step-   351, 356: Moving direction of movable mold-   391 a, 391 b, 392 a, 392 b: Moving direction of slide mold (2)    during mold-opening step-   101: Boundary of cylinder bore-side wall surface of groove-like    coolant passage with respect to each bore-   141 a, 141 b: Half of groove-like coolant passage in circumferential    direction

1. A method for producing a water jacket spacer comprising subjecting asynthetic resin to an injection molding process to produce a waterjacket spacer, the water jacket spacer being disposed in part of agroove-like coolant passage along a circumferential direction, thegroove-like coolant passage being provided to a cylinder block of aninternal combustion engine that has cylinder bores, the injectionmolding process comprising a clamping step that clamps an injectionmold, an injection step that injects the synthetic resin in a moltenstate, a solidification step that cools and solidifies the syntheticresin while keeping pressure, a mold-opening step that opens theinjection mold, and an ejection step that ejects an integrally moldedproduct from the injection mold, the injection mold comprising astationary mold, a movable mold that moves in an upward-downwarddirection with respect to the water jacket spacer, and at least oneslide mold (1) that moves in a direction at an angle of ±15° or lesswith respect to a direction that is perpendicular to a direction inwhich the cylinder bores are arranged, and is perpendicular to a movingdirection of the movable mold, and forming a molding space when clampedby the clamping step, the molding space producing the integrally moldedproduct that comprises at least a first water jacket spacer, a secondwater jacket spacer, and a bridge, the first water jacket spacer and thesecond water jacket spacer being provided so that inner sides thereofare situated opposite to each other, and the bridge linking an innerside or an end of the first water jacket spacer, and an inner side or anend of the second water jacket spacer, and the mold-opening step movingthe movable mold in the upward-downward direction with respect to thewater jacket spacer, and moving the slide mold (1) in a direction at anangle of ±15° or less with respect to the direction that isperpendicular to the direction in which the cylinder bores are arranged,and is perpendicular to the moving direction of the movable mold, toopen the injection mold.
 2. The method for producing a water jacketspacer according to claim 1, wherein the bridge comprises an inter-borebridge that links an inner side of an inter-bore part of the first waterjacket spacer, and an inner side of an inter-bore part of the secondwater jacket spacer, and an end bridge that links the end of the firstwater jacket spacer and the end of the second water jacket spacer. 3.The method for producing a water jacket spacer according to claim 2,wherein the integrally molded product further comprises an inter-bridgebridge that links a center area of the inter-bore bridge and a centerarea of the end bridge that is situated adjacent to the inter-borebridge, or links center areas of the inter-bore bridges that aresituated adjacent to each other.